Dr Pepper vs Diet Barq's root beer: which has more caffeine?

Dr Pepper has more caffeine than Diet Barq's root beer: 41mg vs 0mg in the same 12 oz can. That is a 41mg gap, and since the cans match, the per-serving number is the whole story.

Dr Pepper vs Diet Barq's root beer: the numbers

Sources: Dr Pepper's figure is verified in our Dr Pepper caffeine guide against KDP product facts / Caffeine Informer (source); Diet Barq's root beer's figure is verified in our Diet Barq's root beer guide against Caffeine Informer / Coca-Cola brand data (source).

The concentration gap is the striking part: Dr Pepper packs roughly 342 times the caffeine per ounce. Sipping speed matters at that density; a 12 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.

Which one should you pick?

Pick Diet Barq's root beer when you want the lighter dose or a slower ramp, and Dr Pepper when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.

For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.

Related reading

• Dr Pepper: the full caffeine guide
• Diet Barq's root beer: the full caffeine guide
• The verified caffeine database
• Every drink compared: the comparisons index

FAQ

Does Dr Pepper or Diet Barq's root beer have more caffeine? Dr Pepper: 41mg per 12 oz can versus 0mg per 12 oz can for Diet Barq's root beer.

Which is stronger per ounce? Dr Pepper, at about 3.4mg per fluid ounce versus 0.0mg for Diet Barq's root beer.